Fully cured thermoplastic elastomer, process for its manufacture and applications thereof

ABSTRACT

The present invention provides a fully vulcanized thermoplastic elastomer comprising a rubber phase with a controllable particle size and a spheroidic shape, the preparation and use thereof. Fully vulcanized powdery rubber is blended with plastic by conventional method for blending rubbers, and thus obtaining a fully vulcanized thermoplastic elastomer, which comprises a rubber phase with a controllable particle size and a spheroidic shape, and which shows high tensile strength and high elongation at break, good appearance and good processibility.

The present invention relates to a thermoplastic elastomer, moreparticularly, to a fully vulcanized thermoplastic elastomer obtained byblending method, a process for preparation and use thereof.

Fully vulcanized thermoplastic elastomer, which is prepared by theprocess of mechanically blending elastomer with rigid plastics undercertain conditions, is one kind of new materials that have beendeveloped since 1980s. Such thermoplastic elastomer has the features ofboth plastics and rubbers, namely, showing high elasticity of rubbersunder normal temperature, while being capable of plasticize at elevatedtemperature. In morphology of the fully vulcanized thermoplasticelastomer, the fully crosslinked rubber phase was dispersed into theplastic matrix. Strength, elasticity, thermal resistance and compressionset resistance of the fully vulcanized thermoplastic elastomer aresubstantially improved compared with the un-crosslinked thermoplasticelastomer, due to the crosslinking of rubber phase. Furthermore, thechemical resistance and processing stability are greatly improved, andthe properties of the materials are widely adjustable due to the widerrange of rubber/plastic blending ratio.

The fully vulcanized thermoplastic elastomers obtained by dynamicvulcanization method are known in the art, for example, are described inthe literatures: “Development of fully vulcanized EPDM/PP thermoplasticelastomer”, China Synthetic Rubber Industry, No. 5, P361-364 (1986);“Development of fully cured thermoplastic elastomer of polyolefin”,Chemical Industry and Engineering Progress, No. 5, P16-19 (1987);Mechanical modification of elastomer, editor Zu Yujun, Beijing Scienceand Technology Press, P335-395(1992). The term “dynamic vulcanization”used herein refers to a process of vulcanization by means ofcross-linking agent and intense shear stress when blending rubbers andplastics, the cruxes of which are that the mixing should not be stoppeduntil the vulcanization is finished and there should be sufficientamount of curing agent to ensure the full vulcanization of rubber phase.

Since the full vulcanization of rubber phase in the conventional dynamicvulcanization method was carried out during blending, the requirementsof cross-linking agent, blending temperature, shear rate, blending timeand collaboration therebetween is rather high; additionally, specialblending equipment is required, which leads to high production cost,complex procedure, and incontrollable average particle size of rubberphase and crosslinking degree. Difficulties exist in the production offully vulcanized thermoplastic elastomer of saturated rubber type (e.g.acrylic rubber and silicon rubber), and the requirement in equipment ishigh. In respect of fully vulcanized thermoplastic elastomer, itsphysical properties are greatly influenced by the particle size of therubber phase, the smaller particle size of the rubber phase, the highertensile strength and breaking elongation of the material, and the betterprocessability of the material. The particle size of the rubber phase ofthe fully vulcanized thermoplastic elastomer obtained by dynamicvulcanization is mainly dependent upon the balance between the shearrate and the speed of chemical cross-linking reaction, and thus isdifficult to be very small. As described by Coran A. Y. et al, Rubb.Chem. Technol. 53(1), 141(1980), the average particle size of rubberphase of fully vulcanized thermoplastic elastomer obtained by dynamicvulcanization is 1μ-2μ. In addition, large amounts of rubber isdispersed into plastic matrix because the phase inversion of rubbercontained in the conventional fully vulcanized thermoplastic elastomeris carried out during the melt shearing and curing steps of the dynamicvulcanization method. Therefore, the shape of the rubber phase isirregular, which is adverse to rheological property and processabilityof the fully vulcanized thermoplastic elastomer. Moreover, the articlesproduced with the fully vulcanized thermoplastic elastomer in prior arthave a dark color, that is, it is difficult to obtain an article withlight color, because curing agent has to be used in the dynamicvulcanization method.

One object of the present invention is to provide a fully vulcanizedthermoplastic elastomer, wherein the rubber phase has a particle size of0.02μ-1μ.

Another object of the present invention is to provide a fully vulcanizedthermoplastic elastomer, wherein the rubber phase has a spheroidicshape.

Another object of the present invention is to provide a fully vulcanizedthermoplastic elastomer, wherein the rubber phase has a controllableparticle size and a spheroidic shape.

Yet another object of the present invention is to provide a process forpreparing said fully vulcanized thermoplastic elastomer. Said processuses general rubber/plastic blending equipment, and is a simpleprocedure and could well control particle size and particle sizedistribution of the rubber phase as well as cross-linking degree.

Still another object of the present invention is to provide the use ofsaid thermoplastic elastomer for producing various moulded articles.

According to one aspect of the present invention, the average particlesize of the dispersed phase, i.e. rubber phase, of the fully vulcanizedthermoplastic elastomer is typically 0.02μ-1μ, preferably 0.05μ-0.5μ,more preferably 0.05μ-0.2μ.

According to another aspect of the present invention, the shape of therubber phase of the fully vulcanized thermoplastic elastomer isregularly spheroidic. In one preferable embodiment of this aspect of thepresent invention, the particle size of the rubber phase is 0.02μ-1μ,preferably 0.05μ-0.5μ, more preferably 0.05μ-0.2μ.

In the present fully vulcanized thermoplastic elastomer, the weightratio of rubber phase to plastic matrix is preferably 30:70˜75:25, morepreferably 50:50˜75:25. The rubber phase of said fully vulcanizedthermoplastic elastomer has a gel content of at least 60% by weight,preferably at least 75% by weight.

In the present invention, there is no restriction in the rubber kind ofthe rubber phase of the fully vulcanized thermoplastic elastomer, andwhich can be selected from, for example, the group consisting of fullyvulcanized natural rubber, styrene-butadiene rubber, carboxylatedstyrene-butadiene rubber, nitrile rubber, carboxylated nitrile rubber,chloroprene rubber, polybutadiene rubber, acrylic rubber,butadiene-styrene-vinylpyridine rubber, isoprene rubber, butyl rubber,ethylene-propylene rubber, polysulfide rubber, acrylic-butadiene rubber,silicone rubber, polyurethane rubber, and fluorine rubber.

The plastic matrix of said fully vulcanized thermoplastic elastomercomprises at least one polymer or copolymer thereof selected from thegroup consisting of polyamide, polypropylene, polyethylene, polyvinylchloride, polyurethane, polyester, polycarbonate, polyoxymethylene,polystyrene, polyphenylene oxide, polyphenylene sulfide, polyimide,polysulfone and the like.

The process used for preparing the fully vulcanized thermoplasticelastomer of the present invention comprises blending the fullyvulcanized powdery rubber and the plastic and then pelleting theobtained mixture to form the fully vulcanized thermoplastic elastomer ina rubber/plastic blending equipment by common rubber/plastic blendingmethod. The average particle size of the fully vulcanized powdery rubberused therein is dependent on the particle size of the rubber phasepresent in the fully vulcanized thermoplastic elastomer, which istypically 0.02μ-1μ, preferably 0.05μ-0.5μ, more preferably 0.05μ-2μ. Theweight ratio of the fully vulcanized powdery rubbery to the plastic ispreferably 30:70 to 75:25, more preferably 50.50 to 75:25. For blending,the powdery rubber and the plastic can be mixed atone time;alternatively, a part of powdery rubber and plastic are first mixed toforma blend, which is then mixed with the rest powdery rubber

In preparing the present fully vulcanized thermoplastic elastomer, theplastic matrix can be at least one polymer or copolymer thereof selectedfrom the group consisting of polyamide, polypropylene, polyethylene,polyvinyl chloride, polyurethane, polyester, polycarbonate,polyoxymethylene, polystyrene, polyphenylene oxide, polyphenylenesulfide, polyimide, polysulfone and the like.

The suitable fully vulcanized powdery rubber used in the presentinvention can be the powdery rubber prepared by the process disclosed inChinese Patent Application No. 99125530.5 (Dec. 3, 1999) by the presentinventor, which is incorporated herein by reference. Said powdery rubbercomprises at least one fully vulcanized powdery rubber selected from thegroup consisting of fully vulcanized powdery natural rubber, fullyvulcanized powdery styrene-butadiene rubber, fully vulcanized powderycarboxylated styrene-butadiene rubber, fully vulcanized powdery nitrilerubber, fully vulcanized powdery carboxylated nitrile rubber, fullyvulcanized powdery polybutadiene rubber, fully vulcanized powderychloroprene rubber, fully vulcanized powdery silicone rubber, fullyvulcanized powdery acrylic rubber, fully vulcanized powderystyrene-butadiene-vinylpyridine rubber, fully vulcanized powderyisoprene rubber, fully vulcanized powdery butyl rubber, fully vulcanizedpowdery ethylene-propylene rubber, fully vulcanized powdery polysulfiderubber, fully vulcanized powdery acrylic-butadiene rubber, fullyvulcanized powdery polyurethane rubber, and fully vulcanized powderyfluorine rubber and the like. Said fully vulcanized powdery rubber has agel content of at least 60% by weight, more preferably at least 75% byweight.

The present fully vulcanized powdery rubber can be obtained byvulcanizing the corresponding rubber latex with irradiation. Forexample, the present fully vulcanized powdery rubber can be prepared byirradiating a feed rubber latex which is commercial available orprepared by user, in the presence or absence of a crosslinking agent,with a high-energy irradiation, to vulcanize it fully. The irradiationof high-energy rays can be selected from cobalt source, X-rays, UV rays,and high-energy electron beams, preferably cobalt source. Theirradiation dose is dependent on the kinds and compositions of thelatex. In general, the irradiation dose is selected such that the fullyvulcanized rubber obtained by irradiating and thus vulcanizing saidrubber latex has a gel content of 60% by weight or higher, preferably75% by weight or higher, more preferably 90% by weight or higher. Theirradiation dose can be 0.1 to 30 Mrad (megarads), preferably 0.5 to 20Mrad. If desired, the irradiated latex can be dried to obtain a fullyvulcanized powdery rubber having a particle size that is substantiallythe same as the size of the rubber particles in the latex. The dryingprocess can be carried out by a spray dryer or by precipitation dryingmethod. If the drying is carried out by a spray dryer, the inlettemperature can be controlled at 100 to 200° C., and the outlettemperature at 20 to 80° C.

In the present invention, there is no restriction in the rubber latexused as starting material, and which can be selected from the groupconsisting of natural rubber latex, styrene-butadiene rubber latex,carboxylated styrene-butadiene rubber latex, nitrile rubber latex,carboxylated nitrile rubber latex, chloroprene rubber latex,polybutadiene rubber latex, acrylic rubber latex,butadiene-styrene-vinylpyridine rubber latex, isoprene rubber latex,butyl rubber latex, ethylene-propylene rubber latex, polysulfide rubberlatex, acrylic-butadiene rubber latex, silicone rubber latex,polyurethane rubber latex, and fluorine rubber latex. The size of therubber particles can be varied depending on various end uses.

A cross-linking agent is optionally used in the preparation of thepresent fully vulcanized powdery rubber. The suitable cross-linkingagent can be mono-, di-, tri-, tetra- or multi-functional cross-linkingagent, and any combination thereof. Examples of the monofunctionalcross-linking agent include, but no limited to, octyl (meth)acrylate,isooctyl (meth)acrylate, glycidyl (meth)acrylate; examples of thedifunctional cross-linking agent include, but not limited to,1,4-butandiol di(meth)acrylate, 1,6-hexandiol di(meth)acrylate,diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate,neopentyl glycol di(meth)acrylate, divinyl benzene; examples of thetrifunctional cross-linking agent include, but not limited to,trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate;examples of the tetrafunctional cross-linking agent include, but notlimited to, pentaerythritol tetra(meth)acrylate, ethoxylatedpentaerythritol tetra(meth)acrylate; examples of the multifunctionalcross-linking agent include, but not limited to, di-pentaerythritolpenta(meth)acrylate. In the context of the present invention, the term“(meth)acrylate” means acrylate and methacrylate.

The above-mentioned cross-linking agent can be used alone or in anycombination thereof, as long as it facilitates the irradiationvulcanization.

The amount of the cross-linking agent added varies depending upon thekinds and compositions of rubber latex, and generally is 0.1 to 10% byweight, preferably 0.5 to 9% by weight, more preferably 0.7 to 7% byweight, based on the neat weight of the rubber.

During preparation, blending temperature of the materials is thatsuitable for common plastic processing, which is determined by themelting temperature of the plastic matrix and should be selected withinsuch a range where the plastic matrix is melt completely withoutdecomposition. In addition, conventional processing aids andcompatibilizer for plastic processing can be suitably added to theblended materials, if desired.

The blending equipment used in the present invention istwo roll mill,Banbury mixer, single-screw extruder or twin-screw extruder and thelike.

Compared with the particle size of the rubber phase of the fullyvulcanized thermoplastic elastomer obtained by conventional dynamicvulcanization, the particle size of the rubber phase of the presentfully vulcanized thermoplastic elastomer is controllable, resulting inimproved tensile strength and the breaking elongation, good appearanceand good processibility. Moreover, the rubber phase of the present fullyvulcanized thermoplastic elastomer has a regularly spheroidic shape,which is beneficial to rheological and processing performance.Additionally, it is not necessary to add curing agent when preparing thepresent vulcanized thermoplastic elastomer, thus easier to obtain alight-color article of the fully vulcanized thermoplastic elastomer. Thefully vulcanized thermoplastic elastomer of the present invention isalso easily fabricated into articles with varied colors. The processesof the present invention are simple, of low equipment cost andcontrollable in operation, which meet the requirements for large-scalecommercial production, due to the utilizing of the conventionalrubber/plastic blending equipment and common mixing method.

The fully vulcanized thermoplastic elastomer of the present inventionhas excellent properties and is used in manufacturing various mouldedarticles, such as hoses, corrugated tubes, gaskets, joints, electricalappliances, automotive fittings, building materials and sport equipment.After modifying said fully vulcanized thermoplastic elastomer to improveits flame resistance, the obtained flame-retarding article has a widerscope of application.

In the following examples, the particle size of the rubber phase of thefully vulcanized thermoplastic elastomer is measured by conventionaltransmission electron microscope (TEM) method.

The following specific examples will provide further illustrations ofthe present invention. These examples are not intended, however, tolimit or restrict the scope of the invention as defined in the claims.

FIG. 1 is the TEM micrograph of the sample obtained in Example 2.

EXAMPLES 1

Fully vulcanized powdery styrene-butadiene rubber with an averageparticle size of about 0.1μ (which is prepared as follows: adding 3% ofcross-linking agent trimethylolpropane triacrylate, based on the mass ofdried styrene-butadiene rubber latex, to styrene-butadiene rubber latexDingben-50 (available from Latex Research Center of LanzhouPetrochemical Co., Ltd, GanSu, China), vulcanizing the formulation withthe irradiation dose of 2.5 Mrad, then drying it via spray dryingmethod) and polypropylene (designation: 1300, available from YanshanPetrochemical Co., Ltd, Beijing, China) are blended at a ratio of 70/30by weight, then 0.5% of antioxidant Irganox 1010 (manufactured byCiba-Geigy, Switzerland) was added, based on the total weight of powderystyrene-butadiene rubber and polypropylene. The obtained formulation ispelletized in a ZSK-25 model twin-screw extruder (WP company, Germany).The temperature of the individual sections of the extruder is set at170° C., 190° C., 190° C., 190° C., 190° C., 195° C. (die),respectively. The analysis of thus obtained pellets shows that therubber phase of the thermoplastic elastomer has an average particle sizeof about 0.1μ, and is of a spheroidic shape.

The pellets are injection-moulded into standard specimen bar fortesting. The properties of the fully vulcanized styrene-butadienerubber/polypropylene thermoplastic elastomer tested are listed inTable 1. Whiteness of the thermoplastic elastomer is 35.57 (according toGB2913-88), which enables to dye the articles to any desired colors.

EXAMPLES 2

Fully vulcanized powdery styrene-butadiene rubber with an averageparticle size of about 0.1μ, as described in Example 1, and polystyrene(designation: 666D, available from Yanshan Petrochemical Co., Ltd,Beijing, China) are blended at a ratio of 70/30 by weight, then 0.5% ofantioxidant Irganox 1010 was added, based on the total weight of powderystyrene-butadiene rubber and polystyrene. The obtained formulation ispelletized in a ZSK-25 model twin-screw extruder (WP Company, Germany).The temperature of the individual sections of the extruder is set at170° C., 185° C., 185° C., 185° C., 185° C., 190° C. (die),respectively. The analysis of thus obtained pellets shows that therubber phase of the thermoplastic elastomer has an average particle sizeof about 0.1μ, and is of a spheroidic shape.

The pellets are injection-moulded into standard specimen bar fortesting. The properties of the fully vulcanized styrene-butadienerubber/polystyrene thermoplastic elastomer tested are listed in Table 1.

EXAMPLE 3

The procedure in Example 2 is repeated except that polystyrene isreplaced with high-impact polystyrene (HIPS) (designation: 492J,available from Yanshan Petrochemical Co., Ltd, Beijing, China). Theanalysis of the obtained pellets shows that the rubber phase of thethermoplastic elastomer has an average particle size of about 0.1μ, andis of a spheroidic shape. The properties of the fully vulcanizedstyrene-butadiene rubber/HIPS thermoplastic elastomer tested are listedin Table 1.

EXAMPLE 4

The procedure in Example 1 is repeated except that said polypropylene isreplaced with polypropylene (designation: 1740, available from YanshanPetrochemical Co., Ltd, Beijing, China). The analysis of the obtainedpellets shows that the rubber phase of the thermoplastic elastomer hasan average particle size of about 0.1μ, and is of a spheroidic shape.The properties of the fully vulcanized styrene-butadienerubber/polypropylene thermoplastic elastomer tested are listed in Table1.

EXAMPLE 5

Fully vulcanized powdery carboxylated styrene-butadiene rubber with anaverage particle size of about 0.1μ (which is prepared as follows:adding 3% of cross-linking agent isooctyl acrylate, based on the mass ofdried carboxylated styrene-butadiene rubber latex, to carboxylatedstyrene-butadiene rubber latex XSBRL-54B1 (available from YanshanPetrochemical Co., Ltd, Beijing, China), vulcanizing the formulationwith the irradiation dose of 2.5 Mrad, then drying it via spray dryingmethod) and Nylon-6 (1013B, manufactured by UBE Industries, Ltd., Japan)are blended at a ratio of 75/25 by weight, then 0.5% of antioxidantIrganox 1010 was added, based on the total weight of powderycarboxylated styrene-butadiene rubber and Nylon-6. The obtainedformulation is pelletized in a ZSK-25 model twin-screw extruder (WPCompany, Germany). The temperature of the individual sections of theextruder is set at 210° C., 225° C., 225° C., 225° C., 230° C., 225° C.(die), respectively. The analysis of thus obtained pellets shows thatthe rubber phase of the thermoplastic elastomer has an average particlesize of about 0.15μ, and is of a spheroidic shape.

The pellets are respectively compression-moulded and injection-mouldedinto standard specimen bar for testing. The properties of the fullyvulcanized carboxylated styrene-butadiene rubber/Nylon-6 thermoplasticelastomer tested are listed in Table 1.

EXAMPLE 6

The procedure in Example 5 is repeated except that the weight ratio offully vulcanized powdery carboxylated styrene-butadiene rubber toNylon-6 is changed to 50/50. The analysis of the obtained pellets showsthat the rubber phase of the thermoplastic elastomer has an averageparticle size of about 0.15μ, and is of a spheroidic shape. Theproperties of the fully vulcanized powdery carboxylatedstyrene-butadiene rubber and Nylon-6 thermoplastic elastomer tested arelisted in Table 1.

EXAMPLE 7

Fully vulcanized powdery carboxylated styrene-butadiene rubber as usedin Example 5 and Nylon-6 are blended at a ratio of 70/30 by weight, andthen pelletized in a Brabender single screw extruder. The temperature ofthe individual sections of the extruder is set at 160° C., 190° C., 230°C., 225° C., respectively. The analysis of thus obtained pellets showsthat the rubber phase of the thermoplastic elastomer has an averageparticle size of about 0.15μ, and is of a spheroidic shape.

The pellets are injection-moulded into standard specimen bar for testingThe properties of the fully vulcanized powdery carboxylatedstyrene-butadiene rubber/Nylon-6 thermoplastic elastomer tested arelisted in Table 1.

EXAMPLE 8

Fully vulcanized powdery carboxylated styrene-butadiene rubber with anaverage particle size of about 0.15μ (which is prepared by the sameprocedure of Example 5 except that the irradiation dose is 10 Mrad) andNylon-6 (1013B, available from UBE Industries, Ltd., Japan) are blendedat a ratio of 40/30 by weight, then 0.7% of antioxidant Irganox 1010 wasadded, based on the total weight of powdery carboxylatedstyrene-butadiene rubber and Nylon-6. The obtained formulation ispelletized in a Brabender single screw extruder. The temperature of theindividual sections of the extruder is set at 160° C., 190° C., 230° C.,225° C., respectively. Then the obtained pellets and the above-mentionedcarboxylated styrene-butadiene powdery rubber are blended at a ratio of70/30 by weight, and the final ratio of powdery carboxylatedstyrene-butadiene rubber to Nylon-6 is 70/30 by weight. Then, the finalformulation is pelletized in a ZSK-25 model twin-screw extruder (WPCompany, Germany). The temperature of the individual sections of theextruder is set at 210° C., 225° C., 225° C., 225° C., 230° C. and 225°C. (die), respectively. The analysis of thus obtained pellets shows thatthe rubber phase of the thermoplastic elastomer has an average particlesize of about 0.15μ, and is of a spheroidic shape

The finally obtained pellets are injection-moulded into standardspecimen bar for testing. The properties of the fully vulcanizedcarboxylated styrene-butadiene rubber/Nylon-6 thermoplastic elastomertested are listed in Table 1.

EXAMPLE 9

Fully vulcanized powdery carboxylated nitrile rubber with an averageparticle size of about 0.05μ (which is prepared as follows: adding 3% ofcross-linking agent trimethylol propane triacrylate, based on the massof dried carboxylated nitrile rubber latex, to carboxylated nitrilerubber latex XNBRL (available from Latex Research Center of LanzhouPetrochemical Co., Ltd GanSu, China), vulcanizing the formulation withthe irradiation dose of 10 Mrad, then drying it via spray drying method)and Nylon-6 (1013B, available from UBE Industries, Ltd., Japan) areblended at a ratio of 70/30 by weight, then 0.5% of antioxidant Irganox1010 was added, based on the total weight of powdery carboxylatednitrile rubber and Nylon-6. The obtained formulation is pelletized in aZSK-25 model twin-screw extruder (WP Company, Germany). The temperatureof the individual sections of the extruder is set at 210° C., 225° C.,225° C., 225° C., 230° C. and 225° C. (die), respectively. The analysisof thus obtained pellets shows that the rubber phase of thethermoplastic elastomer has an average particle size of about 0.05μ, andis of a spheroidic shape.

The pellets are injection-moulded into standard specimen bar fortesting. The properties of the fully vulcanized carboxylated nitrilerubber/Nylon-6 thermoplastic elastomer tested are listed in Table 1.

EXAMPLE 10

Fully vulcanized powdery natural rubber with an average particle size ofabout 0.5μ (which is prepared as follows: adding 5% of cross-linkingagent trimethylolpropane triacrylate, based on the mass of dried naturalrubber latex, to natural rubber latex (available from Beijing LatexFactory, China), vulcanizing the formulation with the irradiation doseof 15 Mrad, then drying it via spray drying method) and high densitypolyethylene (HDPE) resin (Designation: J-1, available from BeijingSecond Auxiliaries Factory) are blended at a ratio of 70/30 by weight,then 0.5% of antioxidant Irganox 1010 was added, based on the totalweight of powdery natural rubber and HDPE resin. The obtainedformulation is blended in a Brabender kneader for 2 minutes, with thetemperature of oil bath for the kneader set at 160° C. The analysis ofthus obtained sample shows that the rubber phase of the thermoplasticelastomer has an average particle size of about 0.5μ, and is of aspheroidic shape.

The obtained sample is shaped into sheet by a two roll mill(temperature:160° C.), and then tablettized to obtain the standard specimen fortesting The properties of the fully vulcanized naturalrubber/polyethylene thermoplastic elastomer tested are listed in Table1.

TABLE 1 Tensile Elongation Tensile strength at strength at break Tension100% elongation Shore (MPa) (%) set (%) (MPa) Hardness Example 1 13.7267 24 13.0 27(HD) Example 2 10.1 90 25 — 33(HD) Example 3 8.6 89 18 —28(HD) Example 4 8.7 273 17 8.1 21(HD) 86(HA) Example 5 compressed 17.0175 61 11.8 40(HD) specimen Injection 16.4 216 101 10.5 40(HD) mouldedspecimen Example 6 compressed 29.4 188 96 23.2 — specimen Injection-27.6 200 129 22.5 56(HD) moulded specimen Example 7 19.2 134 38 — 39(HD)Example 8 19.8 167 70 — 46(HD) Example 9 19.1 126 28 — 40(HD) Example 1015.0 438 122 — 86(HA) Test standard ASTM ASTM ASTM ASTM D 412 ASTM D412D412 D412 D2240-95

1. A fully vulcanized thermoplastic elastomer, comprising a rubber phaseand a plastic matrix, wherein an average particle size of the rubberphase of said fully vulcanized thermoplastic elastomer is 0.02μ˜1μ,wherein a shape of the rubber phase of said fully vulcanizedthermoplastic elastomer is spheroidic, wherein the weight ratio of therubber phase to the plastic matrix is 30:70 to 75:25, wherein the rubberphase of said fully vulcanized thermoplastic elastomer comprises atleast one rubber selected from the group consisting of natural rubber,styrene-butadiene rubber, carboxylated styrene-butadiene rubber, nitrilerubber, carboxylated nitrile rubber, polybutadiene rubber, chloroprenerubber, silicone rubber, acrylic rubber, styrene-butadiene-vinylpyridinerubber, isoprene rubber, butyl rubber, polysulfide rubber,acrylic-butadiene rubber, polyurethane rubber, and fluorine rubbers, andwherein the rubber phase is provided by a fully vulcanized powderyrubber prepared by vulcanizing a corresponding rubber latex withirradiation.
 2. The fully vulcanized thermoplastic elastomer accordingto claim 1, wherein said rubber phase has a gel content of at least 60%by weight.
 3. The fully vulcanized thermoplastic elastomer according toclaim 2, wherein the rubber phase has a gel content of at least 75% byweight.
 4. The fully vulcanized thermoplastic elastomer according toclaim 1, wherein the plastic matrix of said fully vulcanizedthermoplastic elastomer comprises at least one polymer or copolymerthereof selected from the group consisting of polyamide, polypropylene,polyethylene, polyvinyl chloride, polyurethane, polyester,polycarbonate, polyoxymethylene, polystyrene, polyphenylene oxide,polyphenylene sulfide, polyimide and polysulfone.
 5. A method comprisingpreparing a moulded article with the vulcanized thermoplastic elastomerof claim
 1. 6. The fully vulcanized thermoplastic elastomer according toclaim 1, wherein the average particle size of said rubber phase is0.05μ-0.2μ.
 7. The fully vulcanized thermoplastic elastomer according toclaim 1, wherein the weight ratio of the rubber phase to the plasticmatrix is 50:50 to 75:25.
 8. The fully vulcanized thermoplasticelastomer according to claim 1, wherein said fully vulcanizedthermoplastic elastomer is prepared by a process comprising the stepsof: (i) providing a fully vulcanized powdery rubber, which is preparedby vulcanizing a corresponding rubber latex with irradiation and (ii)blending the fully vulcanized powdery rubber with a plastic, wherein aweight ratio of the fully vulcanized powdery rubber to the plastic is30:70 to 75:25.
 9. The fully vulcanized thermoplastic elastomeraccording to claim 1, wherein the average particle size of said rubberphase is 0.05μ˜0.5μ.
 10. A process for preparing a fully vulcanizedthermoplastic elastomer, which comprises the steps of (i) providing afully vulcanized powdery rubber as a first starting material, and (ii)blending the fully vulcanized powdery rubber with plastic as a secondstarting material, wherein the fully vulcanized powdery rubber isprepared by vulcanizing a corresponding rubber latex with irradiation,wherein the shape of the fully vulcanized powdery rubber is spheroidic,wherein said fully vulcanized powdery rubber comprises at least onerubber selected from the group consisting of fully vulcanized powderynatural rubber, fully vulcanized powdery styrene-butadiene rubber, fullyvulcanized powdery carboxylated styrene-butadiene rubber, fullyvulcanized powdery nitrile rubber, fully vulcanized powdery carboxylatednitrile rubber, fully vulcanized powdery polybutadiene rubber, fullyvulcanized powdery chloroprene rubber, fully vulcanized powdery siliconerubber, fully vulcanized powdery acrylic rubber, fully vulcanizedpowdery styrene-butadiene-vinylpyridine rubber, fully vulcanized powderyisoprene rubber, fully vulcanized powdery butyl rubber, fully vulcanizedpowdery polysulfide rubber, fully vulcanized powdery acrylic-butadienerubber, fully vulcanized powdery polyurethane rubber, and fullyvulcanized powdery fluorine rubber, and wherein the weight ratio of thefully vulcanized powdery rubber to the plastic is 30:70 to 75:25. 11.The process according to claim 10, wherein the weight ratio of fullyvulcanized powdery rubber to plastic is 50:50 to 75:25.
 12. The processaccording to claim 10, wherein the average particle size of the fullyvulcanized powdery rubber is 0.05μ˜0.5μ.
 13. The process according toclaim 12, wherein the average particle size of the fully vulcanizedpowdery rubber is 0.05μ-0.2μ.
 14. The process according to claim 10,wherein said plastic comprises at least one polymer or copolymer thereofselected from the group consisting of polyamide, polypropylene,polyethylene, polyvinyl chloride, polyurethane, polyester,polycarbonate, polyoxymethylene, polystyrene, polyphenylene oxide,polyphenylene sulfide, polyimide and polysulfone.
 15. The processaccording to claim 10, wherein the first starting material consistsessentially of the fully vulcanized powdery rubber and the secondstarting material consists essentially of the plastic.
 16. The processaccording to claim 10, wherein the average particle size of the fullyvulcanized powdery rubber is 0.02μ˜1μ.
 17. A fully vulcanizedthermoplastic elastomer prepared by blending a rubber that is powderyand fully vulcanized with a plastic to form the elastomer with a rubberphase and a plastic matrix, wherein the fully vulcanized powdery rubberthat is blended with the plastic is prepared by vulcanizing a latexcomprising the rubber with irradiation whereby the rubber phase isformed with particles having a shape that is spheroidic and more regularthan if the rubber phase were formed by dynamic vulcanization by meansof a cross-linking agent and intense shear stress during blending of therubber and the plastic, wherein an average particle size of theparticles in the rubber phase of said fully vulcanized thermoplasticelastomer is 0.02μ-1μ, and wherein the rubber phase of said fullyvulcanized thermoplastic elastomer comprises at least one rubberselected from the group consisting of natural rubber, styrene-butadienerubber, carboxylated styrene-butadiene rubber, nitrile rubber,carboxylated nitrile rubber, polybutadiene rubber, chioroprene rubber,silicone rubber, acrylic rubber, styrene-butadiene-vinylpyridine rubber,isoprene rubber, butyl rubber, polysulfide rubber, acrylic-butadienerubber, polyurethane rubber, and fluorine rubber.